In conventional film/screen radiography, a commonly used patient identification system has the following features.
1. A requisition is filled out by the radiologist ordering a specific exam to be performed on a patient. The requisition is sent to the radiology department.
2. A technologist takes the requisition, an x-ray film cassette, and a portable x-ray generator to the patient bedside.
3. The technologist performs the exam and the film is exposed to x-rays.
4. The requisition is taped to the cassette and the exposed film is taken to the darkroom.
5. A preprinted information card is "flashed" on to the film. Such information includes the patient name, medical record number, birth date, hospital name, current date and other standard information.
6. The film is processed, and the radiology technologist verifies that a "good" image has been recorded.
7. A sticker is applied to the film which records the date, time of exposure, technique, and technologist identification.
8. The finished x-ray film is placed on a light box for review and diagnosis by a radiologist or physician.
Because of the inherent disadvantages of film radiography in the acquisition, storage and transmission of x-ray images, there has been proposed a storage phosphor radiography system. Temporary x-ray images stored in a storage phosphor are converted into an x-ray image digital signal which can be stored, processed and transmitted. As described in U.S. Pat. No. Re. 31,847, reissued Mar. 12, 1985 to Luckey, a photostimulable phosphor sheet is exposed to an image-wise pattern of short wavelength radiation, such as x-ray radiation, to record a latent image pattern in the photostimulable phosphor sheet. The latent image is read out by stimulating the phosphor with a relatively long wavelength stimulating radiation, such as red or infrared light. Upon stimulation, the stimulable phosphor releases emitted radiation of an intermediate wavelength, such as blue or violet light, in proportion to the quantity of x-ray radiation that was received. An x-ray image signal is produced by scanning the stimulable phosphor sheet in a raster pattern by means of a beam of laser light deflected by an oscillating or rotating scanning mirror. The emitted radiation is sensed by a photodetector to produce an electrical x-ray image signal. This signal may then be stored, transmitted, or displayed on a monitor or reproduced as an x-ray film.
As with film-based radiography, storage phosphor radiography requires the matching of an x-ray image with the patient. In situations where many x-rays are taken, such as in an intensive care unit of a large hospital, the management of identification of x-rays with patients can be monumental. In order to process an x-ray image signal as a function of x-ray exposure conditions, it is also desirable to match x-ray exposure conditions and other patient identification data with the x-ray image signal. Such matching results in proper diagnosis by a diagnostician (such as a radiologist) who views the x-ray image on a monitor or x-ray film reproduction.
In a known storage phosphor radiography system, patient information is entered into a workstation and is transferred to a magnetic card. (See, for example, U.S. Pat. No. 4,641,242, issued Feb. 3, 1987, inventor Kimura; U.S. Pat. No. 4,739,480, issued Apr. 19, 1988, inventors Oona et al.; U.S. Pat. No. 4,885,468, issued Dec. 5, 1989, inventor Shimura.) After an x-ray exposure on a storage phosphor is made, a technician places the cassette containing the exposed storage phosphor into a reader and dumps the patient data into the reader by swiping the magnetic card through an associated magnetic card reader. Many problems exist with this system, including double entry of patient data, which is typically entered into a computer at the time a patient is admitted into a hospital. Moreover, the specific ordering of computed radiography cassettes and patient data must be maintained.
U.S. Pat. No. 4,960,994, issued Oct. 2, 1990, inventor Muller et al., discloses a cassette which contains an x-ray film coated with a stimulable phosphor layer and which has a cassette memory which is rigidly attached to the cassette. The memory carries storable, recordable, readable, and erasable data and is attached to the cassette at a position spaced a predetermined distance from a given cassette corner. The rigidly attached memory has four contacts for transfer of data and for power supply. This patent does not disclose the use of a separate bar code on the cassette.
The health care bar code identification systems disclosed in the following patents are not entirely suitable for use in storage phosphor radiography systems: U.S. Pat. No. 4,857,713, issued Aug. 15, 1989, inventor Brown; U.S. Pat. No. 5,006,699, issued Apr. 9, 1991, inventors Felkner et al.; U.S. Pat. No. 4,835,372, issued May 30, 1989, inventors Gombrich et al.; and U.S. Pat. No. 4,857,372, issued Aug. 15, 1989, inventors Gombrich et al.
A storage phosphor radiography patient ID system using a hand-held bar code scanner has been proposed in commonly-assigned, copending U.S. Pat. application Ser. No. 963,036, filed Oct. 19, 1992. The disclosed system records data using a hand-held bar code scanner. Because this image will be recorded, processed, transmitted, and archived digitally by a computer, the exam data also needs to be in digital form to travel with the image. The exam data is read in directly from the bar code scanner by the storage phosphor reader into a header file which is associated with the image file. The image is quality assured by a radiology tech using an electronic view box(video monitor), and the image is printed on film with the necessary information by a laser printer. Thus, no "post-processing" is required.
A more recent development for use in healthcare identification systems is suggested in the brochure entitled "Touch The Future", distributed by Dallas Semiconductor, Dallas, Texas. A solid state read/write memory in a self contained stainless steel can has a self-adhesive backing attachable to a hospital bracelet to provide patient ID. A hospital bedside testing application is also suggested in which the solid state memory container is adhered to a nurse's badge and a reagent cannister. A hand-held meter downloads the information received from these memories into a personal computer. There is no suggestion in this brochure of using the solid state memory container in a storage phosphor radiography system.
A problem therefore exists in storage phosphor radiography apparatus of linking examination information associated with an x-ray exam with the x-ray image recorded in a storage phosphor.